Ecology - Lecture 20 - The Carbon Cycle

Front 1

Atmospheric carbon comes in the form of...

Back 1

...CO₂!

Front 2

What 3 major environmental fluxes influence the carbon cycle?

Back 2

1) Photosynthesis

2) Respiration

3) Decomposition

Front 3

What percentage of the atmosphere is composed of CO₂?

Back 3

0.04%

Front 4

What process(es) does CO₂ play for plants?

Back 4

Used by plants for photosynthesis

A product of plant respiration

Front 5

Global Carbon Cycle:

Where is the largest pool of carbon located?

Back 5

As dissolved inorganic carbon in the ocean.

Front 6

Global Carbon Cycle:

Where do the largest *fluxes* of carbon occur?

Back 6

1) Between the atmosphere and terrestrial vegetation.

2) Between the atmosphere and ocean.

Front 7

What is the average amount of time that a single CO₂ molecule will spend in the atmosphere?

Back 7

5 years

Front 8

How far back of a record of CO₂ levels does the Vostok Ice Core provide us with?

What 2 things have this Ice Core told us about historic CO₂ levels?

Back 8

420,000 years

1) CO₂ concentrations change over time.

2) ΔCO₂ concentrations correlated with Δglobal temperature

Front 9

Describe the process by which "ice cores" allow us to view atmospheric conditions throughout history.

Back 9

When ice forms, bubbles are trapped.
These bubbles have CO₂ (and other atmospheric gasses) which can provide a door to the past.

Front 10

The Vostok Ice Core has showed us that CO₂ concentrations are correlated with _____.

Back 10

Temperature.

Front 11

What compounds make up greenhouse gasses primarily?

What are their respective percentages?

Back 11

1) Water vapor: 35% - 70%

2) CO₂: 9% - 26%

3) Methane (CH₄)
ozone (O₃)
nitrous oxide (N₂O)
hydrofluorocarbons
chlorofluorocarbons

Front 12

What are some aspects of the spatial patterns we've noticed about global warming?

Back 12

- Not all regions are warming the same amount.

- A few areas are cooling.

- Oceans are warming.

Front 13

Approximately what percentage of CO₂ emissions are removed by natural sinks?

What are these two natural sinks, and how does the above percentage split between them?

Back 13

52% of CO₂ emissions are removed by natural sinks

Oceans remove - 26%
Land removes - 26%

Front 14

What percentage of CO₂ emissions remains in the atmosphere?

What is the name of this portion of CO₂ emissions?

Back 14

48% stays in the atmosphere.

Called "The Airborne Fraction"

Front 15

What type of experiment was set up to test the argument that an increase in CO₂ in the atmosphere will be beneficial to plants?

What did these experiments find?

Back 15

Free Air Carbon Enrichment (FACE) rings. [25.13]

- Plants initially increase their primary production.

- This increase was not sustained over time in terrestrial ecosystems [28.11].

Front 16

What are the 3 major greenhouse gasses that have been mentioned in Lecture 19 and 20?

Back 16

N₂O - Nitrous Oxide
CO₂ - Carbon Dioxide
CH₄ - Methane

Front 17

What is the chemical equation for:

Methanogenesis

Back 17

4CH₃OH → 1CO₂ + 2H₂O + 3CH₄

Methanol is converted into methane, carbon dioxide and water.

(Coefficients of products go 1, 2, 3)

Front 18

What environment does Methanogenesis primarily occur in?

What can be a "visual" result of Methanogenesis?

Back 18

- Archaebacteria in *anerobic* environments.

- "Swamp Gas"

Front 19

Who are believed to be the 2 main culprits for increasing methane concentrations?

Back 19

1) COWS

2) Expanding areas occupied by rice paddies.

Front 20

True/False:

Levels of atmospheric methane are leveling off.

Back 20

True

Lecture 20, Slide [9/9 pdf]

Front 21

At what rate does the Keeling Curve tell us that CO₂ is rising per year?

Back 21

CO₂ is now rising at 1.9 ppm (0.5%) per year

Front 22

What span of time does the Keeling Curve cover?

Back 22

~1960 - 2005

Front 23

What 2 contemporary studies/measurements have helped us look at rising CO₂ levels?

Back 23

1) Measurements from Mauna Loa Observatory

2) The "Keeling Curve"